4 envelopes Knox unflavored gelatine
1/2 cup granulated sugar
1 1/2 cups cold water
1 (12 ounce) package semisweet chocolate chips

In a medium saucepan, mix Knox unflavored gelatine with sugar. Blend in water. Let stand 1 minute. Stir over low heat until gelatine is completely dissolved, about 3 minutes.

Add chocolate chips and continue cooking, stirring constantly, until chocolate is melted. With a wire whip or rotary beater, beat mixture until chocolate is blended. Pour into an 8- or 9-inch square pan and chill until firm. To serve, cut into 1-inch squares.

Variations
Rocky Road Blox - Stir in 1/2 cup each chopped nuts and Marshmallow Cr?e
Cherry Fudge Blox - Stir in 1/2 cup chopped maraschino cherries
Fruit 'n' Nut Blox - Stir in 1/2 cup each raisins and chopped nuts